help! how many cc's?

[redneck_c10]

i just bought a 69 model 350. i need to know what size the chambers are in the heads. the id number on the heads is 3932454. i have found a couple pages with some info but not how many cc's they hold. please, if anyone knows a site that can tell me or if u know or have any helpful input it would be great.

[waycool9]

well I do believe that a chevy 350 is a 5.7L, so it should be around 5700cc, but after further research I found it to be 5735 cc.

[kevinthenerd]

When you talk about the cc's of the head, you're usually talking about the actual volume inside the head. It's the volume you use to calculate the compression ratio. The compression ratio is the ratio of the volume at BDC (bottom dead center) vs. TDC (top dead center).

At TDC, the piston crown is assumed to be level with the top of the block deck. Whatever is over or under this is added to the volumes. Dished pistons are going to have a positive value for this volume, but domed pistons are going to have a negative value.

Volume at TDC = volume of head + volume of crown + volume of gasket
Volume at BDC = volume at TDC + stroke*((bore/2)^2)*pi

Compression ratio = Volume at BDC / Volume at TDC

(FYI: Displacement = Volume at BDC - Volume at TDC = stroke*((bore/2)^2)*pi)

Here's the process of discovering these volumes. I learned this in a graduate-level race engine engineering class taught by a guy with years of NASCAR experience. I'm sorry if I forget any details.

First of all, the gasket volume should be listed when you buy the gasket.

Here's how to find the piston volume. Remove your head and put the engine on an engine stand. Rotate the engine so the block deck is perfectly level. Put a degree wheel on the crankshaft. Use a dial gauge and rotate the crankshaft so your piston is at a known height (usually 0.050" below TDC). Record the degree and rotate it the other way. The average of the two values is your TDC, and you should zero your degree wheel to it. (Finding the TDC degree is damn-near impossible with one measurement.) Get a flat piece of plexiglas and drill a hole in it. Get a beaker and fill it up to a known volume with wintergreen rubbing alcohol available at a local drug store. (It's easy to see and it evaporates before rust becomes an issue, making cleanup easy too.) From TDC, move the piston down a known height if you have domed pistons, providing a cylindrical volume you'll have to subtract later. Seal the plexiglas to the block deck with a thin coat of white lithium grease, pushing down to minimize the error from the grease. Before you put down the plexiglas, you might want to use the white lith grease to seal the piston ring a bit too, but use as little as possible. Fill the area above the piston with the alcohol and measure what you have left over to determine the amount of liquid in the volume.

A similar method is used to find the volume of the head. This time, you'll want to be sure that you have springs on the valves to seal the head.

[kevinthenerd]

Originally Posted by waycool9

well I do believe that a chevy 350 is a 5.7L, so it should be around 5700cc, but after further research I found it to be 5735 cc.

That doesn't take a lot of research...

http://www.google.com/search?hl=en&q...=Google+Search

But, if you really want to be technical... a 350 has a bore of 4" and a stroke of 3.48"...

http://en.wikipedia.org/wiki/Small_block_chevy

http://www.google.com/search?hl=en&s...E3&btnG=Search

http://www.google.com/search?hl=en&s...rs&btnG=Search

http://www.google.com/search?hl=en&s...E3&btnG=Search

[Hudson]

Originally Posted by redneck_c10

i just bought a 69 model 350. i need to know what size the chambers are in the heads. the id number on the heads is 3932454. i have found a couple pages with some info but not how many cc's they hold. please, if anyone knows a site that can tell me or if u know or have any helpful input it would be great.

In addition to the great technical definition given above by Kevinthenerd (assuming that you are looking for HEAD volume and not the engine's displacement), you would need to know which 350 V8 it is. GM had a few including one from Chevrolet, Buick, Pontiac, and Oldsmobile (Cadillac used this one in the 1970s)...and they're all different.

[hotrod_chevyz]

3932454 are allowed to be on certain classes of stock SBC race cars that only allow +76cc chamber heads producing no more than 9.0 to 1 C/R when applied to a stock block configuration. Im going to guess they are small valve heads (less than "1.94's").

You could use them for a mildly cammed 2 barrel setup and shoot for 15-17 AVG MPG. If thats not your style and you want it to have some real dig sell them for core and get some big valve heads to "clean up".

[UncleBob]

at least someone was willing to answer the actual question....I was too lazy to spend the 10 seconds of google searches to find the cc's from the head part number

Google is your friend....if you haven't become intimate with it, (or any other good search engine) then spend some time with it, read some how-to's. You can find just about anything with a good search engine if you know how to phrase the search parameters

in this particular example, just searching using the phrase "3932454 SB head", the 3rd link in the list gave you all the data you could ever want for those heads

http://www.chevymania.com/partsid/pa...p=head&block=S